CPU

For those to whom it matters here is some detail from Linux's /proc/cpuinfo

vendor_id

:

CentaurHauls

cpu family

:

6

model

:

7

model name

:

VIA Samuel 2

stepping

:

3

Power Supply

The unit requires a 12V supply. If yours came without one a unit can be easily sourced. I have
bought suitable 12V 3A units on ebay that were advertised as being replacements for LCD displays.
I'm not too sure of the exact dimensions required for the plug, but a 5.5mm external 2.1mm internal
plug seems to fit. (Maplin stock one - part # AQ88V type E).

Expansion

The RAM is soldered to the board and so fixed at 128MB.

The Flash memory is provided by a DOM (Disk On Module) fitted to a standard 44-pin IDE connector.
You can see this in the top right of the picture.

Click on the photo for a larger version.

From an HP briefing document:

"Going forward, new t51xx and t55xx thin clients will not have configurable RAM. For manufacturing
economies of scale, RAM will be installed "down." The t51xx and t55xx units will not include a
SODIMM slot."